1. Field of the Invention
The present invention relates to a laser light irradiation apparatus which has been improved in uniformity over an irradiated surface.
2. Description of the Related Art
In recent years, there is known a technique in which a crystalline silicon film is formed on a glass substrate and a thin film transistor is formed by using the crystalline silicon film.
As a method of obtaining a crystalline silicon film, there is known a technique in which an amorphous silicon film is first formed by a plasma CVD method or the like, and irradiation of a laser light is carried out to the amorphous silicon film to transform it into the crystalline silicon film.
An annealing method with this laser light irradiation is also used for annealing the source and drain regions of a thin film transistor formed in a self-aligned manner.
Although the method with the laser light irradiation is a technique capable of obtaining high crystallinity, there is a problem that the method is disadvantageous for a treatment of a large area.
However, in the case where an active matrix type liquid crystal display device having a large area is manufactured, there are no effective methods under the present situation other than the above-mentioned method of using the laser light.